I have done weddings at Orana Park - up close and personal with animals.
If you want to go up on the hills - The Sign of the Bellbird or other places on the Port Hills ensure you have amazing photos as the views are awesome.
Taking a boat out and anchoring somewhere in the Harbour is a great location if you like the water.
Never performed a wedding there but thinking the Antarctic Centre could be a different location for a wedding.
Heading up to She Chocolat at Governors Bay - done some lovely ceremonies there and also the jetty at Governors Bay.
The beach is ideal and you can make it feel like an overseas destination with your decorations - lots of colour and a relaxed atmosphere.
By the rocks down at Sumner another special place if you don't mind going without pretty shoes or having sand in your shoes.
Cinemas, The Square, riverbanks, by lakes, ponds, beautiful family gardens - the options are endless. Just consider what you will do if its wet.
Always put a wet weather option on the papers you submit to Birth, Deaths and Marriages. Then put in place a wet weather notification plan. If you have it place the hope is you will not need to use it!
Have a brain storming session and get a list of alternative options for you to consider.